President Carter defended the administrations handling of the coal strike yesterday, describing it as "not an exhibition of irresoluteness" but rather the product of "a carefully balanced judgment."

Carter brandished no new threats of government intervention and confined himself to an expression of "hope" that the 160,000 striking members of the United Mine Workers union will ratify a proposed settlement in balloting over the weekend.

Carter's muted rhetoric in response to questions during a nationally televised news conference reflected concern, administration sources said, that threats would create a backlash among the strikers, who are reportedly sharply divided over the proposed contract.

But subtle government pressures continued, with some sources spreading word that the administration may seek a back-to-work injunction under the Taft-Hartley Act without immediately proposing legislation to seize the mines. Many miners have vowed to defy an injunction and indicated they would prefer government seizure, under which labor made major gains during the 1940s.

Labor Secretary Ray Marshall said Wednesday the government was prepared to move "immediately" to reopon the mines if the contract is rejected but said the specific action would hinge on congressional consultations.

Associated Press reported that the administration approached Sen. Edward M. Kennedy (D-Mass.) to engage his help in selling the contract in West Virginia but that Kennedy declined. A Kennedy aide said only that the senator had not been asked to "go to West Virginia" and believed he should confine his role to serving on the Senate Human Resources Committee, which would handle any strike legislation.

Pressures from the union leadership were not so subtle. UMW President Arnold Miller, who had planned to take a back seat in the ratification drive because of his unpopularity among many miners, predicted yesterday in an interview from Oak Hill, W.Va., that rejecting the contract could mean the end of the union.

He said miner definace of an injunction could lead to heavy fines that would bankrupt the union. He also said it could lead to an end to industrywide bargaining and fragment the union's efforts.

Carter, at his news conference at the National Press Club, noted that he had been criticized for acting too late by some and too early by others in finally forcing a settlement last Friday, the 81st day of the record-long coal walkout.

"My own deep commitment is that whenever the collective bargaining system can function, government ought to let it function," he said. "And I think had we precipitously imposed our will in the coal strike deliberations, that effort would have been counterproductive.

"I don't know what the miners will do this weekend. I hope they will vote affirmatively on the negotiated settlement. But I think it was not an exhibition of irresoluteness on our part. It was a carefully balanced judgment about what we should do."

Meanwhile, the possibility of ratification delayed threatened electric power cutbacks and job layoffs in several states, including Maryland and Virginia.

The Labor Department reported that 22,600 factory workers were laid off in 11 eastern states during the week ended Feb. 25 because of power shortages. The total workforce in these states is 7.8 million.